2465 help to fix


max t
 

Hi , recently bought 2465 with fuse blown , i have found negative terminal of C1022 from A3 inverter board corroded and detached from
capacitor , while the board disassembled have changed all electrolytic capacitors
of inverter and regulator board A2 , then switched on the scope
it power up and checked all voltages at J119 everything fine but have troubles , i get smal traces and anything i touch or rotare the trace move from left to the right and viceversa ,

this the video on youtube http://www.youtube.com/watch?v=paTn-lAGfzA&feature=youtu.be

and this image at imageshack https://imagizer.imageshack.us/v2/459x613q90/547/m49i.jpg

before to say U800 is dead
what i can try , thanks for helping.

cheers


 

Its unusual that C1022 would have corrosion on the leads.  That capacitor sits high on a pedestal and has heavier wire leads than most of the others.  Is it possible there is other corrosion inside the case?  Maybe from an extremely humid, aggressive environment?

You say "anything I touch or rotate" causes the trace to shift right/left and the pictures on YouTube show the trace can be positioned at either the left or right side of the screen.  This doesn't seem like U800 to me.  Perhaps others who have diagnosed U800 failures can better describe those symptoms.

I am trouble that ANYTHING will move the trace right or left.  The link on YouTube shows changing the Readout intensity.  Dos the same thing happen when you change the overall intensity (the left most control beneath the CRT)?  Or, if you change the trigger settings (for example) or verticle postion the trace moves?  The controls along the bottom of the display (intensity, focus, etc) connect differently than the controls on the right panel (trigger, position, gain variables, etc).  The bottom edge controls use hardwire connections that change voltages directly at various amplifier pins.  The right edge controls are strobed by the micro-computer and the micro-computer sets operation of the various amplifiers.  The bottom controls may be disturbing a common voltage supply, while the panel controls can only instruct the micro-computer.  This little bit of detective work may help focus your search.

Finally, the most common reason for controls to interact is when they share supply voltages and one of them drags the supply voltage when it is changed.  The bottom front panel controls share +5 voltage from a common trace (that could be corroded if the instrument has been wet in the past).  The next measurement I would make is the voltage on pin 23 of U650.  This voltage should change smoothly as you adjust readout intensity.  Similarly, the voltage at pin 22 of U650 should change smoothly as you change overall intensity.  This will give you a good clue whether its at the control interface or after the display sequencer. 

From: max t
To: TekScopes@...
Sent: Saturday, January 11, 2014 8:01 AM
Subject: [TekScopes] 2465 help to fix

 
Hi , recently bought 2465 with fuse blown , i have found negative terminal of C1022 from A3 inverter board corroded and detached from
capacitor , while the board disassembled have changed all electrolytic capacitors
of inverter and regulator board A2 , then switched on the scope
it power up and checked all voltages at J119 everything fine but have troubles , i get smal traces and anything i touch or rotare the trace move from left to the right and viceversa ,

this the video on youtube http://www.youtube.com/watch?v=paTn-lAGfzA&feature=youtu.be

and this image at imageshack https://imagizer.imageshack.us/v2/459x613q90/547/m49i.jpg

before to say U800 is dead
what i can try , thanks for helping.

cheers




max t
 

Thanks for answer , Yes rotating vertical,intensity,focus,time,trigger the beam moving vertically but everthing slide to left or right itself , the graticule never get red intensity , pin 23 of U650 rotating readout int. ccw 0.116v then rotating cw go down to 0.86v then up again to 0.116v , pin 22 remain to 0.202v even rotating

--- In TekScopes@yahoogroups.com, machine guy <machineguy59@...> wrote:

Its unusual that C1022 would have corrosion on the leads.  That capacitor sits high on a pedestal and has heavier wire leads than most of the others.  Is it possible there is other corrosion inside the case?  Maybe from an extremely humid, aggressive environment?

You say "anything I touch or rotate" causes the trace to shift right/left and the pictures on YouTube show the trace can be positioned at either the left or right side of the screen.  This doesn't seem like U800 to me.  Perhaps others who have diagnosed U800 failures can better describe those symptoms.

I am trouble that ANYTHING will move the trace right or left.  The link on YouTube shows changing the Readout intensity.  Dos the same thing happen when you change the overall intensity (the left most control beneath the CRT)?  Or, if you change the trigger settings (for example) or verticle postion the trace moves?  The controls along the bottom of the display (intensity, focus, etc) connect differently than the controls on the right panel (trigger, position, gain variables, etc).  The bottom edge controls use hardwire connections that change voltages directly at various amplifier pins.  The right edge controls are strobed by the micro-computer and the micro-computer sets operation of the various amplifiers.  The bottom controls may be disturbing a common voltage supply, while the panel controls can only instruct the micro-computer.  This little bit of detective work may help focus your search.

Finally, the most common reason for controls to interact is when they share supply voltages and one of them drags the supply voltage when it is changed.  The bottom front panel controls share +5 voltage from a common trace (that could be corroded if the instrument has been wet in the past).  The next measurement I would make is the voltage on pin 23 of U650.  This voltage should change smoothly as you adjust readout intensity.  Similarly, the voltage at pin 22 of U650 should change smoothly as you change overall intensity.  This will give you a good clue whether its at the control interface or after the display sequencer. 


________________________________
From: max t <maxxim_66@...>
To: TekScopes@yahoogroups.com
Sent: Saturday, January 11, 2014 8:01 AM
Subject: [TekScopes] 2465 help to fix



 
Hi , recently bought 2465 with fuse blown , i have found negative terminal of C1022 from A3 inverter board corroded and detached from
capacitor , while the board disassembled have changed all electrolytic capacitors
of inverter and regulator board A2 , then switched on the scope
it power up and checked all voltages at J119 everything fine but have troubles , i get smal traces and anything i touch or rotare the trace move from left to the right and viceversa ,

this the video on youtube http://www.youtube.com/watch?v=paTn-lAGfzA&feature=youtu.be

and this image at imageshack https://imagizer.imageshack.us/v2/459x613q90/547/m49i.jpg

before to say U800 is dead
what i can try , thanks for helping.

cheers


 

I have not seen this problem before but we can trace the schematic.  My next measurements would be to see if the voltage at pin2 of R352 changes as you turn the intensity and pin 2 of R351 changes as you turn Readout intensity.

But it is concerning that changing settings on the panel (vert pos, etc) changes the horizontal left and right.  That may indicate a bad CRT tube.  I am sure there are other measurements to verify that and perhaps others on the forum will have ideas here. 

For now, I would trace the schematic and check voltages beginning at the intensity knobs. 

From: max t
To: TekScopes@...
Sent: Saturday, January 11, 2014 12:19 PM
Subject: [TekScopes] Re: 2465 help to fix

 
Thanks for answer , Yes rotating vertical,intensity,focus,time,trigger the beam moving vertically but everthing slide to left or right itself , the graticule never get red intensity , pin 23 of U650 rotating readout int. ccw 0.116v then rotating cw go down to 0.86v then up again to 0.116v , pin 22 remain to 0.202v even rotating

--- In TekScopes@..., machine guy wrote:
>
> Its unusual that C1022 would have corrosion on the leads.  That capacitor sits high on a pedestal and has heavier wire leads than most of the others.  Is it possible there is other corrosion inside the case?  Maybe from an extremely humid, aggressive environment?
>
> You say "anything I touch or rotate" causes the trace to shift right/left and the pictures on YouTube show the trace can be positioned at either the left or right side of the screen.  This doesn't seem like U800 to me.  Perhaps others who have diagnosed U800 failures can better describe those symptoms.
>
> I am trouble that ANYTHING will move the trace right or left.  The link on YouTube shows changing the Readout intensity.  Dos the same thing happen when you change the overall intensity (the left most control beneath the CRT)?  Or, if you change the trigger settings (for example) or verticle postion the trace moves?  The controls along the bottom of the display (intensity, focus, etc) connect differently than the controls on the right panel (trigger, position, gain variables, etc).  The bottom edge controls use hardwire connections that change voltages directly at various amplifier pins.  The right edge controls are strobed by the micro-computer and the micro-computer sets operation of the various amplifiers.  The bottom controls may be disturbing a common voltage supply, while the panel controls can only instruct the micro-computer.  This little bit of detective work may help focus your search.
>
> Finally, the most common reason for controls to interact is when they share supply voltages and one of them drags the supply voltage when it is changed.  The bottom front panel controls share +5 voltage from a common trace (that could be corroded if the instrument has been wet in the past).  The next measurement I would make is the voltage on pin 23 of U650.  This voltage should change smoothly as you adjust readout intensity.  Similarly, the voltage at pin 22 of U650 should change smoothly as you change overall intensity.  This will give you a good clue whether its at the control interface or after the display sequencer. 
>
>
> ________________________________
> From: max t > To: TekScopes@...
> Sent: Saturday, January 11, 2014 8:01 AM
> Subject: [TekScopes] 2465 help to fix
>
>
>
>  
> Hi , recently bought 2465 with fuse blown , i have found negative terminal of C1022 from A3 inverter board corroded and detached from
> capacitor , while the board disassembled have changed all electrolytic capacitors
> of inverter and regulator board A2 , then switched on the scope
> it power up and checked all voltages at J119 everything fine but have troubles , i get smal traces and anything i touch or rotare the trace move from left to the right and viceversa ,
>
> this the video on youtube http://www.youtube.com/watch?v=paTn-lAGfzA&feature=youtu.be
>
> and this image at imageshack https://imagizer.imageshack.us/v2/459x613q90/547/m49i.jpg
>
> before to say U800 is dead
> what i can try , thanks for helping.
>
> cheers
>




max t
 

Values on those pins is fine , about R352 levels from -4.97v to +4.97v
and R351 from 0v to +4.98v , looking the schematic seems to be ok ,
i have upload a new video with more details of scope rotating pots

this the video
http://www.youtube.com/watch?v=QaHsLDqqg4k&feature=youtu.be

regarding corrosions ..the scope is very clean there no traces
of that i have changed all electrolitics but they was almost
fine maybe the c1022 with broken terminal it was defective
or while assembled too much forced or manipulated then with age
disconnected.

--- In TekScopes@yahoogroups.com, machine guy <machineguy59@...> wrote:

I have not seen this problem before but we can trace the schematic.  My next measurements would be to see if the voltage at pin2 of R352 changes as you turn the intensity and pin 2 of R351 changes as you turn Readout intensity.

But it is concerning that changing settings on the panel (vert pos, etc) changes the horizontal left and right.  That may indicate a bad CRT tube.  I am sure there are other measurements to verify that and perhaps others on the forum will have ideas here. 

For now, I would trace the schematic and check voltages beginning at the intensity knobs. 


________________________________
From: max t <maxxim_66@...>
To: TekScopes@yahoogroups.com
Sent: Saturday, January 11, 2014 12:19 PM
Subject: [TekScopes] Re: 2465 help to fix


 

I have never seen anything like that.  You are able to put the trace nearly anywhere on the screen but it is usually right of center.  The trace that shows in the video looks like the cursor from the readout board.

The fact that you can position the trace right or left, mostly right, seems to say the U800 is working (but not necessarily right).  I am bewildered but will think about it and post back.

Perhaps someone with more experience on these will be better help to you.

Mac

From: max t <maxxim_66@...>
To: TekScopes@...
Sent: Sunday, January 12, 2014 12:24 AM
Subject: [TekScopes] Re: 2465 help to fix

 
Values on those pins is fine , about R352 levels from -4.97v to +4.97v
and R351 from 0v to +4.98v , looking the schematic seems to be ok ,
i have upload a new video with more details of scope rotating pots

this the video
http://www.youtube.com/watch?v=QaHsLDqqg4k&feature=youtu.be

regarding corrosions ..the scope is very clean there no traces
of that i have changed all electrolitics but they was almost
fine maybe the c1022 with broken terminal it was defective
or while assembled too much forced or manipulated then with age
disconnected.

--- In TekScopes@..., machine guy wrote:
>
> I have not seen this problem before but we can trace the schematic.  My next measurements would be to see if the voltage at pin2 of R352 changes as you turn the intensity and pin 2 of R351 changes as you turn Readout intensity.
>
> But it is concerning that changing settings on the panel (vert pos, etc) changes the horizontal left and right.  That may indicate a bad CRT tube.  I am sure there are other measurements to verify that and perhaps others on the forum will have ideas here. 
>
> For now, I would trace the schematic and check voltages beginning at the intensity knobs. 
>
>
> ________________________________
> From: max t
> To: TekScopes@...
> Sent: Saturday, January 11, 2014 12:19 PM
> Subject: [TekScopes] Re: 2465 help to fix




Don Black <donald_black@...>
 

Have you tried tapping the instrument (gently) to see if it's sensitive to vibration. I think it would have to be very touchy to get these results from the mere vibration of turning a knob but it just seems so general that it's possible. While it could be the CRT it doesn't look like it to me so don't slash your wrists just yet. I've never worked on one of these but is it possible to measure the deflection voltage going to the tube. You should be able to see it jumping all over the place in sympathy with the trace movement.
At least you've won weird fault of the month award.

Don Black.
PS can someone advise if this model overheats if operated with the covers off and needs a desk fan blowing into it while working on it?

On 12-Jan-14 6:47 PM, machine guy wrote:
 
I have never seen anything like that.  You are able to put the trace nearly anywhere on the screen but it is usually right of center.  The trace that shows in the video looks like the cursor from the readout board.

The fact that you can position the trace right or left, mostly right, seems to say the U800 is working (but not necessarily right).  I am bewildered but will think about it and post back.

Perhaps someone with more experience on these will be better help to you.

Mac
From: max t
To: TekScopes@...
Sent: Sunday, January 12, 2014 12:24 AM
Subject: [TekScopes] Re: 2465 help to fix

 
Values on those pins is fine , about R352 levels from -4.97v to +4.97v
and R351 from 0v to +4.98v , looking the schematic seems to be ok ,
i have upload a new video with more details of scope rotating pots

this the video
http://www.youtube.com/watch?v=QaHsLDqqg4k&feature=youtu.be

regarding corrosions ..the scope is very clean there no traces
of that i have changed all electrolitics but they was almost
fine maybe the c1022 with broken terminal it was defective
or while assembled too much forced or manipulated then with age
disconnected.

--- In TekScopes@..., machine guy wrote:
>
> I have not seen this problem before but we can trace the schematic.  My next measurements would be to see if the voltage at pin2 of R352 changes as you turn the intensity and pin 2 of R351 changes as you turn Readout intensity.
>
> But it is concerning that changing settings on the panel (vert pos, etc) changes the horizontal left and right.  That may indicate a bad CRT tube.  I am sure there are other measurements to verify that and perhaps others on the forum will have ideas here. 
>
> For now, I would trace the schematic and check voltages beginning at the intensity knobs. 
>
>
> ________________________________
> From: max t
> To: TekScopes@...
> Sent: Saturday, January 11, 2014 12:19 PM
> Subject: [TekScopes] Re: 2465 help to fix







This email is free from viruses and malware because avast! Antivirus protection is active.



 

I can attest to the need for a bench fan when running this scope without a case.  I use a small clip on fan that can be pointed directly at the instrument.

My first thought for this problem was tht one of the Horiz leads was loose from the scope.  They are accessible from the bottom when the case is removed.  But then I saw the trace can be moved to the left side of the screen.  This seems to say the horiz is working.

I still lean to the idea that something is bleeding the power when knobs are turned but I cant think how since it didn't show when the OP measured voltages as he turned pots.

Im stumped.  Not quitting, just stumped.

From: Don Black
To: TekScopes@...
Sent: Sunday, January 12, 2014 2:36 AM
Subject: Re: [TekScopes] Re: 2465 help to fix

 
Have you tried tapping the instrument (gently) to see if it's sensitive to vibration. I think it would have to be very touchy to get these results from the mere vibration of turning a knob but it just seems so general that it's possible. While it could be the CRT it doesn't look like it to me so don't slash your wrists just yet. I've never worked on one of these but is it possible to measure the deflection voltage going to the tube. You should be able to see it jumping all over the place in sympathy with the trace movement.
At least you've won weird fault of the month award.

Don Black.
PS can someone advise if this model overheats if operated with the covers off and needs a desk fan blowing into it while working on it?

On 12-Jan-14 6:47 PM, machine guy wrote:
 
I have never seen anything like that.  You are able to put the trace nearly anywhere on the screen but it is usually right of center.  The trace that shows in the video looks like the cursor from the readout board.

The fact that you can position the trace right or left, mostly right, seems to say the U800 is working (but not necessarily right).  I am bewildered but will think about it and post back.

Perhaps someone with more experience on these will be better help to you.

Mac
From: max t mailto:maxxim_66@...
To: TekScopes@...
Sent: Sunday, January 12, 2014 12:24 AM
Subject: [TekScopes] Re: 2465 help to fix

 
Values on those pins is fine , about R352 levels from -4.97v to +4.97v
and R351 from 0v to +4.98v , looking the schematic seems to be ok ,
i have upload a new video with more details of scope rotating pots

this the video
http://www.youtube.com/watch?v=QaHsLDqqg4k&feature=youtu.be

regarding corrosions ..the scope is very clean there no traces
of that i have changed all electrolitics but they was almost
fine maybe the c1022 with broken terminal it was defective
or while assembled too much forced or manipulated then with age
disconnected.

--- In TekScopes@..., machine guy mailto:machineguy59@... wrote:
>
> I have not seen this problem before but we can trace the schematic.  My next measurements would be to see if the voltage at pin2 of R352 changes as you turn the intensity and pin 2 of R351 changes as you turn Readout intensity.
>
> But it is concerning that changing settings on the panel (vert pos, etc) changes the horizontal left and right.  That may indicate a bad CRT tube.  I am sure there are other measurements to verify that and perhaps others on the forum will have ideas here. 
>
> For now, I would trace the schematic and check voltages beginning at the intensity knobs. 
>
>
> ________________________________
> From: max t mailto:maxxim_66@...
> To: TekScopes@...
> Sent: Saturday, January 11, 2014 12:19 PM
> Subject: [TekScopes] Re: 2465 help to fix






This email is free from viruses and malware because avast! Antivirus protection is active.




max t
 

Did some steps , tracing back around U650 sequencer i have found
sick Q155 e-c low resistence changed it and while the A1 board disassembled have recap whole electrolitics , now scope
is working start without errors but traces very blard
and cannot adjust well also scale illum. not working
this the new video

http://www.youtube.com/watch?v=TnInYagdtQk&feature=youtu.be

--- In TekScopes@yahoogroups.com, machine guy <machineguy59@...> wrote:

I can attest to the need for a bench fan when running this scope without a case.  I use a small clip on fan that can be pointed directly at the instrument.

My first thought for this problem was tht one of the Horiz leads was loose from the scope.  They are accessible from the bottom when the case is removed.  But then I saw the trace can be moved to the left side of the screen.  This seems to say the horiz is working.

I still lean to the idea that something is bleeding the power when knobs are turned but I cant think how since it didn't show when the OP measured voltages as he turned pots.

Im stumped.  Not quitting, just stumped.


________________________________
From: Don Black <donald_black@...>
To: TekScopes@yahoogroups.com
Sent: Sunday, January 12, 2014 2:36 AM
Subject: Re: [TekScopes] Re: 2465 help to fix



 
Have you tried tapping the instrument (gently) to see if it's sensitive to vibration. I think it would have to be very touchy to get these results from the mere vibration of turning a knob but it just seems so general that it's possible. While it could be the CRT it doesn't look like it to me so don't slash your wrists just yet. I've never worked on one of these but is it possible to measure the deflection voltage going to the tube. You should be able to see it jumping all over the place in sympathy with the trace movement.
At least you've won weird fault of the month award.

Don Black.
PS can someone advise if this model overheats if operated with the
covers off and needs a desk fan blowing into it while working on
it?

On 12-Jan-14 6:47 PM, machine guy wrote:

 

I have never seen anything like that.  You are able to put the trace nearly anywhere on the screen but it is usually right of center.  The trace that shows in the video looks like the cursor from the readout board.


The fact that you can position the trace right or left, mostly right, seems to say the U800 is working (but not necessarily right).  I am bewildered but will think about it and post back.


Perhaps someone with more experience on these will be better help to you.


Mac

From: max t mailto:maxxim_66@...
To: TekScopes@yahoogroups.com
Sent: Sunday, January 12, 2014 12:24 AM
Subject: [TekScopes] Re: 2465 help to fix



 
Values on those pins is fine , about R352 levels from -4.97v to +4.97v
and R351 from 0v to +4.98v , looking the
schematic seems to be ok ,
i have upload a new video with more
details of scope rotating pots

this the video
http://www.youtube.com/watch?v=QaHsLDqqg4k&feature=youtu.be

regarding corrosions ..the scope is very
clean there no traces
of that i have changed all electrolitics
but they was almost
fine maybe the c1022 with broken
terminal it was defective
or while assembled too much forced or
manipulated then with age
disconnected.

--- In TekScopes@yahoogroups.com, machine guy mailto:machineguy59@ wrote:

I have not seen this problem before
but we can trace the schematic.  My
next measurements would be to see if the
voltage at pin2 of R352 changes as you
turn the intensity and pin 2 of R351
changes as you turn Readout intensity.

But it is concerning that changing
settings on the panel (vert pos, etc)
changes the horizontal left and right. 
That may indicate a bad CRT tube.  I am
sure there are other measurements to
verify that and perhaps others on the
forum will have ideas here. 

For now, I would trace the
schematic and check voltages beginning
at the intensity knobs. 


________________________________
From: max t mailto:maxxim_66@
To: TekScopes@yahoogroups.com
Sent: Saturday, January 11, 2014
12:19 PM
Subject: [TekScopes] Re: 2465 help
to fix






________________________________

This email is free from viruses and malware because avast! Antivirus protection is active.


 

Congratulations.  That looks like pretty good progress.  It makes sense that a failed Q155 could effect all traces.  Im not sure how changing the intensity settings was able to affect Q155.  But obviously, it did.  again congratulations on the progress.

What you have now could be channel noise and/or miss-adjustment of the CRT screen currents.  A previous technician may have tried all the knobs in a futile attempt at diagnosis.  Anything can happen that way.  I would focus on why the scale illumination doesn't work (failed lamps?) in the remote chance there is another power fault.

As for the blurred traces.  The readout numbers do not appear to be blurred in the YouTube video.  The calibrator traces look like mine do when the ground on the probe is longer than 1 inch of wire.  Try setting the bandwidth limit to 20 MHz and see if the traces clear up.  Then do the CRT adjustments on page 5-4 of the service manual.  This should sharpen the traces so you can search for any other problems.   

From: max t
To: TekScopes@...
Sent: Sunday, January 12, 2014 3:32 AM
Subject: [TekScopes] Re: 2465 help to fix

 
Did some steps , tracing back around U650 sequencer i have found
sick Q155 e-c low resistence changed it and while the A1 board disassembled have recap whole electrolitics , now scope
is working start without errors but traces very blard
and cannot adjust well also scale illum. not working
this the new video

http://www.youtube.com/watch?v=TnInYagdtQk&feature=youtu.be

--- In TekScopes@..., machine guy wrote:
>
> I can attest to the need for a bench fan when running this scope without a case.  I use a small clip on fan that can be pointed directly at the instrument.
>
> My first thought for this problem was tht one of the Horiz leads was loose from the scope.  They are accessible from the bottom when the case is removed.  But then I saw the trace can be moved to the left side of the screen.  This seems to say the horiz is working.
>
> I still lean to the idea that something is bleeding the power when knobs are turned but I cant think how since it didn't show when the OP measured voltages as he turned pots.
>
> Im stumped.  Not quitting, just stumped.
>
>
> ________________________________
> From: Don Black
> To: TekScopes@...
> Sent: Sunday, January 12, 2014 2:36 AM
> Subject: Re: [TekScopes] Re: 2465 help to fix
>
>
>
>  
> Have you tried tapping the instrument (gently) to see if it's sensitive to vibration. I think it would have to be very touchy to get these results from the mere vibration of turning a knob but it just seems so general that it's possible. While it could be the CRT it doesn't look like it to me so don't slash your wrists just yet. I've never worked on one of these but is it possible to measure the deflection voltage going to the tube. You should be able to see it jumping all over the place in sympathy with the trace movement.
> At least you've won weird fault of the month award.
>
> Don Black.
> PS can someone advise if this model overheats if operated with the
> covers off and needs a desk fan blowing into it while working on
> it?
>
> On 12-Jan-14 6:47 PM, machine guy wrote:
>
>  
> >
> >I have never seen anything like that.  You are able to put the trace nearly anywhere on the screen but it is usually right of center.  The trace that shows in the video looks like the cursor from the readout board.
> >
> >
> >The fact that you can position the trace right or left, mostly right, seems to say the U800 is working (but not necessarily right).  I am bewildered but will think about it and post back.
> >
> >
> >Perhaps someone with more experience on these will be better help to you.
> >
> >
> >Mac
> >
> >From: max t mailto:maxxim_66@...
> >To: TekScopes@...
> >Sent: Sunday, January 12, 2014 12:24 AM
> >Subject: [TekScopes] Re: 2465 help to fix
> >
> >
> >
> > 
> >Values on those pins is fine , about R352 levels from -4.97v to +4.97v
> >and R351 from 0v to +4.98v , looking the
> schematic seems to be ok ,
> >i have upload a new video with more
> details of scope rotating pots
> >
> >this the video
> >http://www.youtube.com/watch?v=QaHsLDqqg4k&feature=youtu.be
> >
> >regarding corrosions ..the scope is very
> clean there no traces
> >of that i have changed all electrolitics
> but they was almost
> >fine maybe the c1022 with broken
> terminal it was defective
> >or while assembled too much forced or
> manipulated then with age
> >disconnected.
> >
> >--- In TekScopes@..., machine guy mailto:machineguy59@ wrote:
> >>
> >> I have not seen this problem before
> but we can trace the schematic.  My
> next measurements would be to see if the
> voltage at pin2 of R352 changes as you
> turn the intensity and pin 2 of R351
> changes as you turn Readout intensity.
> >>
> >> But it is concerning that changing
> settings on the panel (vert pos, etc)
> changes the horizontal left and right. 
> That may indicate a bad CRT tube.  I am
> sure there are other measurements to
> verify that and perhaps others on the
> forum will have ideas here. 
> >>
> >> For now, I would trace the
> schematic and check voltages beginning
> at the intensity knobs. 
> >>
> >>
> >> ________________________________
> >> From: max t mailto:maxxim_66@
> >> To: TekScopes@...
> >> Sent: Saturday, January 11, 2014
> 12:19 PM
> >> Subject: [TekScopes] Re: 2465 help
> to fix
> >
> >
> >
> >
>
>
>
>
> ________________________________
>
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